The term "more cockamamie" refers to something that is silly, absurd or ridiculous. Its antonyms include words like logical, rational, sensible, and reasonable. Another antonym could be practical or pragmatic, both of which refer to a more grounded and realistic approach. These antonyms suggest a level of thought and reasoning that is based on evidence, fact and practicality. While the term 'more cockamamie' willingly describes an idea, statement, or system that is unsound or ridiculous, the opposite words showcase a more serious and prudent way of thinking. Thus, the antonyms of "more cockamamie" represent a mindset that is grounded in sanity, logic, and rationality.